const { SourceMapGenerator } = require('source-map')

const map = new SourceMapGenerator({
  file: 'source-mapped.js'
})

map.addMapping({
  generated: {
    line: 10,
    column: 35
  },
  source: 'foo.js',
  original: {
    line: 33,
    column: 2
  },
  name: 'christopher'
})

console.log(map.toString())
